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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Posted on 7 December 2011 by Rob Honeycutt

Peter Sinclair, from Climate Denial Crock of the Week, has a new video out. This one is a simple but to-the-point message from Dr. Richard Alley of Penn State. It's a point that I've tried to make many times myself in online debates with those in denial over climate change. It's not about the hockey stick. It's not about models. It's about...

As Peter Sinclair says, the 'hockey stick' is not the proof of the physics of 'greenhouse' gas-caused warming, it's simply evidence of the effects that such gases are having.

And the 'hockey stick' is just one line of evidence. Anyone who claims that the 'hockey stick' is broken has to explain why physics and other lines of empirical evidence are also collectively broken, or are lying through their respective metaphorical teeth.

I'm not sure if I will ever understand the specific and exclusive focus on Mann's 1998 paper. I'm not sure also if the fake skeptics who do specifically and exclusively focus on the paper realize that he, and many many others, have performed paleoclimate work since then. Let's imagine a world without Mann 1998 - what do we have? Mann 2008. Ljungqvist 2010. Moberg 2005. Those are just the "hockey sticks" of surface temperatures too (often NH temps), several exist with sea ice, glacial ice, oceanic temperatures, need I go on?

Richard Alley has also produced Earth the operators manual. This has been shown on PBS. Richard Alley right off the bat says that he is a registered republican. One of my cases I like to make is this is not a lefty loony thing. I also like to bring up Barry Bickmore's presentation,http://bbickmore.wordpress.com/2011/11/11/how-to-avoid-the-truth-about-climate-change/.

As Dr. Alley says, the 'brocken hockey stick' false narrative makes for a good story for those who don't want to believe the scientific evidence is correct. And it's a real problem when those who influence public policy say "I don't understand science, but I know the climate scientists are wrong."

If you don't know anything about medical science, and you don't trust doctors, who do you go to when you become ill?

Nobody wants to be screwed ( - snip -), especially when the screwing isn't readily apparent. Chest pain is readily apparent. As I've said before, in my more cynical moments (roughly 23.9 hours a day) I favor the prognosis that it's going to take several years of obvious climate change in the US before the culture starts to transform, and climate change of the type that hits the economy from several directions. AGW needs to present a clear and present danger--again, like chest pain. Suddenly, trust in climate scientists will bloom, apologies will be issued, and Watts will claim that he was always on board--just playing devil's advocate, in the same role that crackers and hackers perform for the online security industry.

That might be an interesting followup paper on the psychology of denial: "Escape Pods: What Happens to Committed Doubters When the Writing is On the Wall?"

The problem is that if we have to wait that long we are screwed, because it will then be far too late to properly mitigate, and adaptation will instead become the only viable, primary option. That, and the need to very suddenly cut off emissions, causing exactly the sort of wholesale disruption of economies and lifestyles that deniers pretend is being asked of them now, but is in fact unnecessary as long as we start soon, with considered and intelligent moderation, rather than waiting until later when moderation will no longer be an option and panic instead drives policy.

Just to clarify that thought, you must remember that we are talking about climate change, not climate events. One or two unbelievably long, bad droughts, or storm seasons, or crop losses, or floods or heat waves or whatever are simply events which are symptoms of the permanent change that has taken place.

Once people experience these, it is too late to undo the damage not of the particular event but rather of the inherent and ongoing cause, the changed climate. Events like those will necessarily and unalterably repeat and intensify. We can begin to take action then, but the world and the climate will already have changed (for the worse).

It would rather be like insisting that you actually die of cancer before you submit to those so-annoying radiation and chemotherapy treatments, just to be sure that you weren't wasting your time with a doctor who really can't otherwise prove to you that your cancer is terminal.

“Some of you really ought to read Andrew W. Montford's "The Hockey Stick Illusion: Climategate and the Corruption of Science" to get a thorough understanding of how the science underlying the totally unproven hypothesis of catastrophic anthropogenic global warming has been manipulated.

“The use of bristlecone pine tree rings as temperature proxies, questionable statistical methods and appending instrumental temperatures has been shown to be deliberately misleading.”

Statements like the above should not go unchallenged. Unfortunately, it takes a lot of time and effort to patrol the comment threads of media websites like NPR's. In many respects, it is a thankless job, but one that has to be done in my opinion.

I love Richard Alley videos! He kind of squeaks in a way that superbly expresses an exasperation with which I identify. But I'm a scientist. For people who aren't scientists, maybe there are other voices that might be able to sell the message more effectively. I'd like to see an experiment done -- get James Earl Jones or, uh, I dunno ... a variety of great speaking voices and see if this has an effect on how the message is received. There's a reason commercial interests use spokespeople rather than company directors (who should know more about whatever topic it is) to sell goods. Results of this experiment could be appended to the next edition of the Debunking Handbook.

One thing that might tip the balance little - it doesn't hit right at home or the economy but it sure might be visual and compelling. An aerial shot of a group of cruise liners, side by side on Sept 15th. At the North Pole. With no ice in sight. If we are lucky - and this is a terrible thing to have to say - the current trends from PIOMass mean we should be there around 2015/16.

A climate model based on the "global energy balance" has provided new evidence for human-induced climate change, according to its creators. Using this simple model, researchers in Switzerland conclude that it is extremely likely (>95% probability) that at least 74% of the observed warming since 1950 has been caused by human activity.

I am a high school teacher who is trying to figure out this climate change issue. I have shown An Inconvenient Truth to my class and tried to show where qualified PhD's think the movie gets things wrong. The hockey stick is one of the many things that have been shown to be controversial.

I am confused why this video downplays the hockey stick (and never refutes that the stick is "broken") when it is one of only 2 scientific evidences that Al Gore used in An Inconvenient Truth to try to tie temperature with CO2. (the other was the ice-core data from the last 650,000 yrs) The entire rest of the movie was about the effects of warming and the actions we need to take.

If the hockey stick is taken out, the most well-known presentation of AGW loses half of its evidence.

Here is my question: Can I now present to my classes that the hockey stick argument has been discarded by the AGW proponents?

SirNubWub: "Can I now present to my classes that the hockey stick argument has been discarded by the AGW proponents?"

No, but you can present to your classes the fact that there is a mountain of evidence demonstrating the reality of AGW. The very fact that you have arrived at SkS means that you can access a wide range of that science. Better still, pose some questions to your classes and have them use SkS as a research library, as others have already done.

SirNubwub - "Can I now present to my classes that the hockey stick argument has been discarded by the AGW proponents?"

No, you cannot. There are multiple "hockey sticks", whether speaking of Arctic ice decline, CO2 increase, temperature records, etc., and even in the limited arena of temperature reconstruction over the last 1500-2000 years - multiple hockey sticks.

That's the data. That's the facts. Telling your students that this is _not_ the case is doing them no good, giving them mis-information.

We're changing the climate - at a rate >10x that of the PETM, one of the fastest natural changes on record. Likely results are massive changes in cropland distribution, increased extrema weather (hurricanes, heat waves, etc.), greatly changed precipitation (floods and droughts), and so on. A century or so down the line the sea level rises will be undeniable, heading to what might become perhaps 50-100 meters rise given "Business as Usual".

Nothing broken about the "hockey stick". Multiple reconstructions of temperature show it, multiple analyses of sea level rise show it - all as a result of our actions over the last 150 years, changing aspects of the climate 10x faster (or more) than nature has ever shifted matters.

Please, please don't mislead your students by telling them there is nothing to worry about.

1) I have not seen "An Inconvenient Truth" but I have read the book. Consequently I can state very confidently that your claim that the " hockey stick" was half of Gore's evidence is false.

2) I suspect Dr Alley, like I, does not consider a popular presentation of the evidence to be the evidence. Rather, he relies on the scientific papers from a small sample of which Al Gore gleaned his evidence. In the last 20 years there have been 2,350 scientific papers contributing evidence towards the hypothesis of AGW (1990 to present). I am disinclined to ignore all that evidence because a popular presentation fails to capture it all.

3) You can now present to your classes that the 1998 Hockey Stick paper (Mann, Bradley and Hughes, 1998) is now out of date, and that some flaws in the first attempt at a new method of discovering the history of Earth's climate have since been corrected by later papers. You can also tell them that those later papers show a very similar, hockey stick pattern, even though they do not suffer from the flaws of MBH 98, differing mostly in that they show a colder Little Ice Age, but equivalent temperatures in the Medieval Warm Period.

4) Finally, you should tell them, as you should already, that science is a collaborative project because no single person is wise enough to avoid all, or even most possible mistakes. By mutual criticism, however, mistakes get weeded out. However, scientists are human and will often stick with comfortable theories long after their refutation. Science, as it was once said, advances one funeral at a time. Therefore the fact that one or two PhDs can be found who take exception to something Gore said has very little relevance. The question that you should put to your students is, does Gore accurately present the contents of the IPCC AR4, ie, the consensus of climate scientists.

SirNubWub…. I would highly suggest watching the full presentation given by Dr Alley from which this video is taken. It can be found in the comments on Peter Sinclair's YouTube channel.

I would also highly recommend watching Dr Alley's AGU lecture titled "The Biggest Control Knob."

It's great you are here looking for accurate information. The best place to find it is in the actual published literature. Every article you find on this site will have full citations to the supporting literature.

You're quite welcome. I would encourage you to take the recommendations that the others have made above to heart. You are the steward of a precious cargo: young minds. It is a trust given you, one that entails a great responsibility.

Given the extreme levels of disinformation in the media about climate science and the massive amounts of dissembling websites in the blog-o-sphere, it's extremely difficult to know whom to trust for reliable information about the science.

This website is created precisely for those just like you: people who have an interest in learning, but have been exposed to much that is simply incorrect about the science.

There is an immense amount of reference material discussed here (4,700+ threads, all replete with links to original peer-reviewed sources) and it can be a bit difficult at first to find an answer to your questions. That's why we recommend that Newcomers, Start Here and then learn The Big Picture.

I also recommend watching this video on why CO2 is the biggest climate control knob in Earth's history, per Rob Honeycutt's sage advice above.

Further general questions can usually be be answered by first using the Search function in the upper left of every Skeptical Science page to see if there is already a post on it (odds are, there is). If you still have questions, use the Search function located in the upper left of every page here at Skeptical Science and post your question on the most pertinent thread.

Remember to frame your questions in compliance with the Comments Policy and lastly, to use the Preview function below the comment box to ensure that any html tags you're using work properly.

I would recommend using the information on NASA's site. All your students will of course know and respect the work of NASA and will therefore accept what their scientists say as the true facts about global warming.

NASA has some very good educational material on their site which I use all the time to convince people that AGW is real, man-made and potentially dangerous.

SirNubwub and his students may benefit from a review of fingerprints. There are many, many independent lines of evidence for AGW. The hockeystick, which has been replicated many times, relies on modeling and proxy analysis which might not be very engaging for your class.

Instead, show this video. Then compare the AGW hypothesis for observed climate changes to an alternative (e.g., it's the sun) with reference to facts like the stratosphere is cooling, nights warm faster than days, there's less infrared escaping to space, etc. Ask them: Which provides a better explanation?

One thing SirNubwub's high school students might be able to relate to - because it's not high powered science - is the Japanese cherry blossom festivals. http://arnoldia.arboretum.harvard.edu/pdf/articles/1893.pdf

This item needs a bit of 'teachering' to condense for initial introduction to students. But it shows them, and us, that scientific analysis and conclusions are based on meticulous record-keeping. In this case, records maintained for an entirely unrelated purpose can provide evidence of something we were expecting from theory - namely physics.

And this fantastic historical record is perfect for scientists to work on. The 'teachering' I'd do would be to separate the historical aspect out, then show how scientists can extract the statistics lying there, waiting for compilation.

Climate Change Skepticism - It's not about the science. It's political. Like the tobacco companies who came before them, "[their] product is doubt"!
If you're trying to create doubt, you make it sound simple. You only have to beat on one thing. You imply "this thing is wrong so it's ALL wrong".

It is propaganda, the essence of which is:
--- addressed exclusively to the "masses", not to scientists;
--- call their attention to your "facts";
--- persuade the audience your fact is "real";
--- don't give them a chance to think about any other facts, keep them focused on yours;
--- engage their emotions, NOT their intellect.
There are tens of millions of people out there ripe for such an approach.

When climategate broke, I told friendly skeptics 'the hockey stick doesn't matter'. That's because the subject is global heating, not atmospheric heating. SURE the hockey stick is important, if you want to know how global heating might impact our atmosphere and hence, our climate. But GLOBAL heating must be proven in the oceans, where 95% of all Earth's thermal mass (influenced by radiative factors) is located. You can turn the celebrated 'hockey stick' upside down, and Earth is still heating, if the ocean's show heating.

Its like you were standing on a scale with 10 other guys, and you say the scale is going to go down because you've been on a diet. But the other guys weigh twice as much as you, and they are gaining weight. Lose all the weight you want to, it doesn't change the uptick of the scale.